Re: [PATCH v2 07/11] scsi: ufs: ufs-qcom: Fixup PAM-4 TX L0_L1_L2_L3 adaptation pattern length
From: Manivannan Sadhasivam
Date: Wed Mar 04 2026 - 10:18:42 EST
On Wed, Mar 04, 2026 at 05:53:09AM -0800, Can Guo wrote:
> If HS-G6 Power Mode change handshake is successful and outbound data Lanes
> are expected to transmit ADAPT, M-TX Lanes shall be configured as
>
> if (Adapt Type == REFRESH)
> TX_HS_ADAPT_LENGTH_L0_L1_L2_L3 = PA_PeerRxHsG6AdaptRefreshL0L1L2L3.
> else if (Adapt Type == INITIAL)
> TX_HS_ADAPT_LENGTH_L0_L1_L2_L3 = PA_PeerRxHsG6AdaptInitialL0L1L2L3.
>
> On some platforms, the ADAPT_L0_L1_L2_L3 duration on Host TX Lanes is only
> a half of theoretical ADAPT_L0_L1_L2_L3 duration TADAPT_L0_L1_L2_L3 (in
> PAM-4 UI) calculated from TX_HS_ADAPT_LENGTH_L0_L1_L2_L3.
>
> For such platforms, the workaround is to double the ADAPT_L0_L1_L2_L3
> duration by uplifting TX_HS_ADAPT_LENGTH_L0_L1_L2_L3. UniPro initializes
> TX_HS_ADAPT_LENGTH_L0_L1_L2_L3 during HS-G6 Power Mode change handshake,
> it would be too late for SW to update TX_HS_ADAPT_LENGTH_L0_L1_L2_L3 post
> HS-G6 Power Mode change. Update PA_PeerRxHsG6AdaptRefreshL0L1L2L3 and
> PA_PeerRxHsG6AdaptInitialL0L1L2L3 post Link Startup and before HS-G6
> Power Mode change, so that the UniPro would use the updated value during
> HS-G6 Power Mode change handshake.
>
> Signed-off-by: Can Guo <can.guo@xxxxxxxxxxxxxxxx>
> ---
> drivers/ufs/host/ufs-qcom.c | 175 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 175 insertions(+)
>
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 5eb12a999eb1..3a9279066192 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -1079,10 +1079,185 @@ static void ufs_qcom_override_pa_tx_hsg1_sync_len(struct ufs_hba *hba)
> dev_err(hba->dev, "Failed (%d) set PA_TX_HSG1_SYNC_LENGTH\n", err);
> }
>
> +/**
> + * ufs_qcom_double_t_adapt_l0l1l2l3 - Create a new adapt that doubles the
> + * adaptation duration TADAPT_L0_L1_L2_L3 derived from the old adapt.
> + *
> + * @old_adapt: Original ADAPT_L0_L1_L2_L3 capability
> + *
> + * ADAPT_length_L0_L1_L2_L3 formula from M-PHY spec:
> + * if (ADAPT_range_L0_L1_L2_L3 == COARSE) {
> + * ADAPT_length_L0_L1_L2_L3 = [0, 12]
> + * ADAPT_L0_L1_L2_L3 = 215 x 2^ADAPT_length_L0_L1_L2_L3
> + * } else if (ADAPT_range_L0_L1_L2_L3 == FINE) {
> + * ADAPT_length_L0_L1_L2_L3 = [0, 127]
> + * TADAPT_L0_L1_L2_L3 = 215 x (ADAPT_length_L0_L1_L2_L3 + 1)
> + * }
> + *
> + * To double the adaptation duration TADAPT_L0_L1_L2_L3:
> + * 1. If adapt range is COARSE (1'b1), new adapt = old adapt + 1.
> + * 2. If adapt range is FINE (1'b0):
> + * a) If old adapt length is < 64, (new adapt + 1) = 2 * (old adapt + 1).
> + * b) If old adapt length is >= 64, set new adapt to 0x88 using COARSE
> + * range, because new adapt get from equation in a) shall exceed 127.
> + *
> + * Examples:
> + * ADAPT_range_L0_L1_L2_L3 | ADAPT_length_L0_L1_L2_L3 | TADAPT_L0_L1_L2_L3 (PAM-4 UI)
> + * 0 3 131072
> + * 0 7 262144
> + * 0 63 2097152
> + * 0 64 2129920
> + * 0 127 4194304
> + * 1 8 8388608
> + * 1 9 16777216
> + * 1 10 33554432
> + * 1 11 67108864
> + * 1 12 134217728
> + *
> + * Return: new adapt.
> + */
> +static inline u32 ufs_qcom_double_t_adapt_l0l1l2l3(u32 old_adapt)
No need of 'inline' keyword in a .c file. Same comment to other helpers.
Also, can you change the '_l0l1l2l3' suffix to something like '_level' or
'_length'?
> +{
> + u32 adapt_length = old_adapt & 0x7F;
Please add a define for 0x75
> + u32 new_adapt;
> +
> + /* Adapt range == COARSE */
> + if (old_adapt & 0x80) {
This one also.
> + new_adapt = (adapt_length + 1) | 0x80;
> + } else {
> + if (adapt_length < 64)
And this one.
> + new_adapt = (adapt_length << 1) + 1;
> + else
> + new_adapt = 0x88;
> + }
> +
> + return new_adapt;
> +}
> +
> +static inline void ufs_qcom_limit_max_gear(struct ufs_hba *hba,
> + enum ufs_hs_gear_tag gear)
> +{
> + struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> + struct ufs_pa_layer_attr *pwr_info = &hba->max_pwr_info.info;
> + struct ufs_host_params *host_params = &host->host_params;
> +
> + host_params->hs_tx_gear = gear;
> + host_params->hs_rx_gear = gear;
> + pwr_info->gear_tx = gear;
> + pwr_info->gear_rx = gear;
> +
> + dev_warn(hba->dev, "Limited max gear of both sides to HS-G%d\n", gear);
s/both sides/host and device
> +}
> +
> +static void ufs_qcom_fixup_tx_adapt_l0l1l2l3(struct ufs_hba *hba)
> +{
> + struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> + struct ufs_pa_layer_attr *pwr_info = &hba->max_pwr_info.info;
> + struct ufs_host_params *host_params = &host->host_params;
> + u32 adapt_l0l1l2l3, new_adapt, actual_adapt;
Can you shorten adapt_l0l1l2l3?
> + bool limit_speed = false;
> + int err;
> +
> + if (host->hw_ver.major != 0x7 || host->hw_ver.minor > 0x1 ||
> + host_params->hs_tx_gear <= UFS_HS_G5 ||
> + pwr_info->gear_tx <= UFS_HS_G5)
> + return;
> +
> + err = ufshcd_dme_get(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTINITIALL0L1L2L3), &adapt_l0l1l2l3);
> + if (err)
> + goto out;
> +
> + if (adapt_l0l1l2l3 > ADAPT_L0L1L2L3_LENGTH_MAX) {
> + dev_err(hba->dev, "PA_PeerRxHsG6AdaptInitialL0L1L2L3 value (0x%x) exceeds MAX.\n",
Nit: remove full stop at the end
> + adapt_l0l1l2l3);
> + err = -EINVAL;
-ERANGE
> + goto out;
> + }
> +
> + new_adapt = ufs_qcom_double_t_adapt_l0l1l2l3(adapt_l0l1l2l3);
> + dev_dbg(hba->dev, "Original PA_PeerRxHsG6AdaptInitialL0L1L2L3 value = 0x%x, new value = 0x%x\n",
> + adapt_l0l1l2l3, new_adapt);
> +
> + /*
> + * 0x8C is the max possible value allowed by UniPro v3.0 spec, some HWs
> + * can accept 0x8D but some cannot.
> + */
> + if (new_adapt <= ADAPT_L0L1L2L3_LENGTH_MAX ||
> + (new_adapt == ADAPT_L0L1L2L3_LENGTH_MAX + 1 && host->hw_ver.minor == 0x1)) {
> + err = ufshcd_dme_set(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTINITIALL0L1L2L3),
> + new_adapt);
> + if (err)
> + goto out;
> +
> + err = ufshcd_dme_get(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTINITIALL0L1L2L3),
> + &actual_adapt);
> + if (err)
> + goto out;
> +
> + if (actual_adapt != new_adapt) {
> + limit_speed = true;
> + dev_warn(hba->dev, "Failed to update host PA_PeerRxHsG6AdaptInitialL0L1L2L3 to new value 0x%x, actual value = 0x%x\n",
This goes beyond 100 column width. Please consider shortening up. Applies to
other prints as well.
> + new_adapt, actual_adapt);
> + }
> + } else {
> + limit_speed = true;
> + dev_warn(hba->dev, "New PA_PeerRxHsG6AdaptInitialL0L1L2L3 value (0x%x) is too large!\n",
> + new_adapt);
> + }
> +
> + err = ufshcd_dme_get(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTREFRESHL0L1L2L3), &adapt_l0l1l2l3);
> + if (err)
> + goto out;
> +
> + if (adapt_l0l1l2l3 > ADAPT_L0L1L2L3_LENGTH_MAX) {
> + dev_err(hba->dev, "PA_PeerRxHsG6AdaptRefreshL0L1L2L3 value (0x%x) exceeds MAX.\n",
> + adapt_l0l1l2l3);
> + err = -EINVAL;
-ERANGE
> + goto out;
> + }
> +
> + new_adapt = ufs_qcom_double_t_adapt_l0l1l2l3(adapt_l0l1l2l3);
> + dev_dbg(hba->dev, "Original PA_PeerRxHsG6AdaptRefreshL0L1L2L3 value = 0x%x, new value = 0x%x\n",
> + adapt_l0l1l2l3, new_adapt);
> +
> + /*
> + * 0x8C is the max possible value allowed by UniPro v3.0 spec, some HWs
> + * can accept 0x8D but some cannot.
> + */
> + if (new_adapt <= ADAPT_L0L1L2L3_LENGTH_MAX ||
> + (new_adapt == ADAPT_L0L1L2L3_LENGTH_MAX + 1 && host->hw_ver.minor == 0x1)) {
> + err = ufshcd_dme_set(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTREFRESHL0L1L2L3),
> + new_adapt);
> + if (err)
> + goto out;
> +
> + err = ufshcd_dme_get(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTREFRESHL0L1L2L3),
> + &actual_adapt);
> + if (err)
> + goto out;
> +
> + if (actual_adapt != new_adapt) {
> + limit_speed = true;
> + dev_warn(hba->dev, "Failed to update host PA_PeerRxHsG6AdaptRefreshL0L1L2L3 to new value 0x%x, actual value = 0x%x\n",
> + new_adapt, actual_adapt);
> + }
> + } else {
> + limit_speed = true;
> + dev_warn(hba->dev, "New PA_PeerRxHsG6AdaptRefreshL0L1L2L3 value (0x%x) is too large!\n",
> + new_adapt);
I'm assuming it is safe to continue despite the warnings.
- Mani
--
மணிவண்ணன் சதாசிவம்